Yong Sik Yoon

Comparative analysis of radiofrequency ablation and surgical resection for colorectal liver metastases

Purpose To evaluate the comparative therapeutic efficacy of radiofrequency ablation (RFA) and hepatic resection for the treatment of colorectal liver metastasis (CRLM). Methods Between 1996 and 2008, 177 patients underwent RFA, 278 underwent hepatic resection and 27 underwent combination therapy for CRLM. Comparative analysis of clinical outcomes was performed including number of liver metastases, tumor size, and time of CRLM. Results Based on multivariate analysis, overall survival (OS) correlated with the number of liver metastases and the use of combined chemotherapy (P < 0.001, respectively). Disease-free survival (DFS) also correlated with the number of liver metastases (P < 0.001). In the 226 patients with solitary CRLM < 3 cm, OS and DFS rates did not differ between the RFA group and the resection group (P = 0.962 and P = 0.980). In the 70 patients with solitary CRLM ≥ 3 cm, DFS was significantly lower in the RFA group as compared with the resection group (P = 0.015). Conclusion The results indicate that RFA may be a safe alternative treatment for solitary CRLM less than 3 cm, with outcomes equivalent to those achieved with hepatic resection. A randomized controlled study comparing RFA and resection for patients with single small metastasis would help to determine the most efficient treatment modalities for CRLM.

Long-term Prognosis of Crohn's Disease and Its Temporal Change Between 1981 and 2012: A Hospital-based Cohort Study from Korea

Background:To date, no large-scale studies have evaluated the prognosis of Crohns disease (CD) over a period of 3 decades in non-Caucasian populations. The aims of this study were to update the current information on the long-term prognosis of CD using a large series of patients and to evaluate changes in treatment paradigms over time and their impact on the prognosis of CD in Korea. Methods:We retrospectively analyzed 2043 Korean patients with CD who visited the Asan Medical Center. The study subjects were divided into 3 groups according to the year of diagnosis (cohort 1: 1981–2000, cohort 2: 2001–2005, and cohort 3: 2006–2012). Results:Azathioprine/6-mercaptopurine and anti–tumor necrosis factor agents have been used increasingly more frequently and earlier over the past 30 years, with a 5-year cumulative probability of prescription of 28.9% and 1.4%, respectively, in cohort 1 and 88.1% and 23.7%, respectively, in cohort 3 (P < 0.001). A total of 726 patients (35.5%) underwent intestinal resection, with a cumulative probability of intestinal resection 10, 20, and 30 years after diagnosis of 43.5%, 70.0%, and 76.1%, respectively. The cumulative probability of surgery was significantly lower in cohort 3 than in cohort 1 (P = 0.012). Early use of azathioprine/6-mercaptopurine was significantly associated with delayed need for intestinal resection by multivariate Cox analysis (hazard ratio: 0.63, 95% confidence interval: 0.46–0.85). Conclusions:Korean patients with CD may have a similar clinical course to Westerners, as indicated by the intestinal resection rate. The surgery rate has decreased over time, and early use of azathioprine/6-mercaptopurine was related to its decrease.

Effectiveness of biofeedback therapy in the treatment of anterior resection syndrome after rectal cancer surgery.

BACKGROUND: Although anterior resection syndrome commonly occurs after anal sphincter-saving surgery, no standard treatment option is currently available. OBJECTIVE: The aim of the present study was to evaluate the clinical effectiveness of biofeedback in patients with anterior resection syndrome after sphincter-saving surgery for rectal cancer. DESIGN: This study was a retrospective review of data collected during the course of treatment. SETTINGS: Patients were treated at a teaching hospital (Asan Medical Center) in Seoul, Korea, from January 2003 through December 2008. PATIENTS: Patients who received biofeedback therapy for anterior resection syndrome after rectal cancer surgery were included. MAIN OUTCOME MEASURES: The Cleveland Clinic Florida fecal incontinence score, number of bowel movements per day, a visual analog scale for assessing patient satisfaction, and anorectal manometry were used to assess outcome of biofeedback treatment. RESULTS: After biofeedback therapy, significant improvements were observed in fecal incontinence score (P < .001), number of bowel movements (P < .001), and anorectal manometry data (maximum resting pressure, P = .010; maximum squeeze pressure, P = .006; rectal capacity, P = .003). Compared with patients who started biofeedback treatment less than 18 months after surgery, those who started biofeedback at 18 months or longer after surgery showed greater improvements in fecal incontinence score (P = .032). Only patients with fecal incontinence as the primary symptom showed significant improvements in all variables, including fecal incontinence score, P < .001; defecation frequency, P < .001; and anorectal manometry (maximum resting pressure, P = .027; maximum squeeze pressure, P = .021; rectal capacity, P = .004). Patients who received radiation therapy in addition to surgery reported a significantly higher satisfaction score than those receiving surgery alone (P = .041). LIMITATIONS: This is a nonrandomized retrospective study. Anorectal manometry was not regularly performed in all patients. CONCLUSIONS: Biofeedback therapy produced significant clinical benefits for patients with severe fecal incontinence and may be an effective treatment for patients with anterior resection syndrome after surgery for rectal cancer.

Comparison of recurrence patterns between ≤5 years and >5 years after curative operations in colorectal cancer patients

To identify characteristics of recurrent colorectal cancer in terms of follow‐up periods, that is, ≤5 years and >5 years after curative operations

Effects of intravenous dexmedetomidine on low-dose bupivacaine spinal anaesthesia in elderly patients

Dexmedetomidine (DMT) has been shown to prolong spinal anaesthesia. We evaluated the effects of intravenous DMT on low‐dose bupivacaine spinal anaesthesia in elderly patients.

Risk factors for complications after bowel surgery in Korean patients with Crohn's disease.

Purpose To assess the incidence and factors predictive of early postoperative complications in Korean patients who undergo surgery for Crohns disease (CD). Methods We retrospectively assessed 350 patients (246 males, 104 females; mean age, 30 ± 9 years) who underwent surgery for primary or recurrent CD at Asan Medical Center between January 1991 and May 2010. The incidence and predictive factors of early postoperative complications were analyzed by both univariate and multivariate analyses. Results Of the 350 patients, 81 patients (23.1%) developed postoperative complications, the most common being septic complications (54 patients), including 19 cases of wound infection. Thirty patients (8.6%) required re-operations, and only one patient died. Multivariate analysis showed that four factors were independently associated with a high risk of early postoperative complications; preoperative moderate to severe anemia (hematocrit concentration <30%; odds ratio [OR], 3.1; 95% confidence interval [CI], 1.6 to 5.9), hypoalbuminemia (serum albumin level <3.0 g/dL; OR, 2.6; 95% CI, 1.4 to 4.7), emergency surgery (OR, 4.0; 95% CI, 1.5 to 10.6), and covering stoma (OR, 2.6; 95% CI, 1.3 to 5.4). Correction of preoperative moderate to severe anemia and hypoalbuminemia decreased the incidence of postoperative complications. Mean hospital stay was significantly longer in patients with than without postoperative complications (31.3 ± 27.2 days vs. 10.3 ± 3.8 days, P < 0.001). Conclusion Preoperative anemia, low albumin level, emergency surgery, and covering stoma significantly increased the risk of early postoperative complications in patients with CD. Correcting preoperatively deficient nutritional factors may reduce postoperative morbidities.

Validation of the seventh edition of the American Joint Committee on Cancer tumor-node-metastasis (AJCC TNM) staging in patients with stage II and stage III colorectal carcinoma: analysis of 2511 cases from a medical centre in Korea

Aim  The sixth and seventh editions of the American Joint Committee on Cancer (AJCC) tumor‐node‐metastasis (TNM) system for patients with stage II and stage III colorectal carcinoma (AJCC‐6 and AJCC‐7) were compared.

The Role of Diverting Stoma After an Ultra-low Anterior Resection for Rectal Cancer.

Purpose A diverting stoma is known to reduce the consequences of distal anastomotic failure following colorectal surgery. The aim of this study was to evaluate the efficacy of a diverting stoma after an ultra-low anterior resection (uLAR) for rectal cancer. Methods Between 2000 and 2007, 836 patients who underwent an uLAR were divided into two groups, depending on the fecal diversion: 246 received fecal diversion, and 590 had no diversion. Patient- and disease-related variables were compared between the two groups. Results Thirty-two of the 836 patients (3.8%) had immediate anastomosis-related complications and required reoperation. Anastomosis leakage comprised 72% of the complications (23/32). The overall immediate complication rate was significantly lower in patients with a diverting stoma (0.8%, 2/246) compared to those without a diverting stoma (5.1%, 30/590; P = 0.005). The fecal diversion group had lower tumor location, lower anastomosis level, and more preoperative chemo-radiation therapy (P < 0.001). In total, 12% of patients in the diverting stoma group had complications either in making or reversing the stoma (30/246). Conclusion The diverting stoma decreased the rate of immediate anastomosis-related complications. However, the rate of complications associated with the diverting stoma was non-negligible, so strict criteria should be applied when deciding whether to use a diverting stoma.

Mismatch repair status in sporadic colorectal cancer: Immunohistochemistry and microsatellite instability analyses

Background and Aim:  The aim of the present study was to evaluate associations between mismatch repair (MMR) status and clinicopathological characteristics and prognosis using immunohistochemistry (IHC) and microsatellite instability (MSI) analyses in a prospective cohort of a large number of accumulated samples.

Acute kidney injury after infrarenal abdominal aortic aneurysm surgery: a comparison of AKIN and RIFLE criteria for risk prediction

BACKGROUND Although both Acute Kidney Injury Network (AKIN) and risk, injury, failure, loss, and end-stage (RIFLE) kidney disease criteria are frequently used to diagnose acute kidney injury (AKI), they have rarely been compared in the diagnosis of AKI in patients undergoing surgery for infrarenal abdominal aortic aneurysm (AAA). This study investigated the incidence of, and risk factors for, AKI, defined by AKIN and RIFLE criteria, and compared their ability to predict mortality after infrarenal AAA surgery. METHODS This study examined 444 patients who underwent infrarenal AAA surgery between January 1999 and December 2011. Risk factors for AKI were assessed by multivariable analyses, and the impact of AKI on overall mortality was assessed by a Coxs proportional hazard model with inverse probability of treatment weighting (IPTW). Net reclassification improvement (NRI) was used to assess the performance of AKIN and RIFLE criteria in predicting overall mortality. RESULTS AKI based on AKIN and RIFLE criteria occurred in 82 (18.5%) and 55 (12.4%) patients, respectively. The independent risk factors for AKI were intraoperative red blood cell (RBC) transfusion and chronic kidney disease (CKD) by AKIN criteria, and age, intraoperative RBC transfusion, preoperative atrial fibrillation, and CKD by RIFLE criteria. After IPTW adjustment, AKI was related to 30 day mortality and overall mortality. NRI was 15.2% greater (P=0.04) for AKIN than for RIFLE criteria in assessing the risk of overall mortality. CONCLUSIONS Although AKI defined by either AKIN or RIFLE criteria was associated with overall mortality, AKIN criteria showed better prediction of mortality in patients undergoing infrarenal AAA surgery.